Motilin is a gastrointestinal hormone which stimulates gastric motor activity in hunger. Motilin is considered to be useful as a therapeutic for, e.g., improving gastric motor activity.
Similar to common physiologically active peptides, motilin is hardly absorbed orally since it shows poor gastrointestinal absorptivity. Such physiologically active substances showing poor oral absorption are generally administered through injection. However, injection is not a preferred route of administration because it is painful, there are potential risky side effects including amyotrophy, it is inconvenient, particularly for individual patient use, and is often limited to institutional treatments.
Recently rectal administration of drugs has again been considered and the administration of, in particular, physiologically active peptides in the form of suppositories has attracted attention. However, there is no motilin preparation suitable for rectal administration capable of maintaining a therapeutically effective blood concentration of motilin, since it is only slightly absorbed if at all through the rectum.
Accordingly, motilin preparations for rectal administration, whereby the absorption of motilin through the rectum is promoted, are needed.